Grinding machine



Dec. 2, 1958 o. E. HILL n 2,862,338

l GRINDING MACHINE Filed April l2, 1957 4 Sheets-Sheet 1 l/o o INVENToR v A r Tag/v5 Y Dec. 2, 1958 o. E. HILL GRINDING MACHINE Filed April 12, 1957 4 Sheets-Sheet 2 fig? INVENTOR O/VA E H/L Ldhm Y ATTO/@NKY o. E. HILL GRINDING- MACHINE:

4 Sheets-Sheet 3 Filed Aprll 12, 1957 United ^IStates lPatent O GnlNnrNG MACHINE Oiva E. Hill, Worcester, Mass., assiguor to Norton Company, Worcester, Mass., a corporation Yof Massachusetts Application April 12, 1957, Serial No. 652,418

9 Claims. (ci. Y51-103) compensating mechanism for advancing the grinding l wheel before each pass of the truing tool across the operative face of the grinding wheel.

Another objectv is to provide a mechanism for imparting an unwind and a wind motion to the wheel feed mechanism each time the feed mechanism is actuated to facilitate taking up back-lash in the feed mechanism parts. Another object is to provide an oscillatable feed unit having an independent feed mechanism for advancing the grinding wheel before each pass of the truing tool and means to oscillate the feed unit to impart an unwind and a wind motion to the feed mechanism at the time of each feeding movement. Other objects will be in part obvious or in part pointed out hereinafter.

One embodiment of the invention has been illustrated in the drawings, in which:

Fig. 1 is a fragmentary side elevation of a centerless grinding machine having parts broken away and shown in section; 1

Fig. 2 is a fragmentary vertical sectional view on an enlarged scale taken approximately on the line 2--2 of Fig. l through the wheel slide and the feed compensating mechanism;

Fig. 3 is a fragmentary front elevation, on an enlarged scale, of the feed compensating mechanism as shown in Fig. l partly broken away and shown in section;

Fig. 4 is a fragmentary vertical sectional View, on an enlarged scale, taken approximately on the line 4 4 of Fig. 2;

Fig. 5 is a vertical sectional Viewtaken approximately on the line 5 5 of Fig. 3 through one of `the feed compensator units.

Fig. 6 is a plan View on an enlarged scale, of the grinding wheel and regulating wheel truing apparatus;V

Fig. 7 is a Vertical sectional view, on an kenlarged scale, taken approximately on the line 7-7 of Fig. 1 showing the workrest and the grinding wheel truing tool mounting;

Fig. 8 is an end elevation of the work guide and truing mechanism as shown in Fig. 6;

Fig. 9 is a fragmentary sectional view on an enlarged scale, taken approximately onthe line 9--9 of Fig. 6 through the truing tool mounting;

Fig. l0 is a fragmentary sectional view taken approxi- ICC 2 mately on the line 1lb- 10 of Fig. 9 through the truing tool support; and

Fig. 1l is a combined hydraulic and electric diagram of the actuating mechanisms and the controls therefor.

A centerless grinding machine has been illustrated in the drawings comprising a base 10 which supports a transversely adjustable grinding wheel slide 11 on a pair of parallel anti-friction slideways 12 (only one of which is shown in the drawings). The wheel slide 11 serves as a support for a rotatable wheel spindle 13 which carries a rotatable grinding wheel 14.

A driving mechanismvis provided for the wheel spindle 13 comprising an electric motor 15 which is adjustably mounted on the upper surface of the wheel slide 11. The motor 15 is provided with a motor shaft 16 having a multiple V-groove pully 17 which is connected by multiple V-belts 18 with a multiple V-groove pulley 19 which is mounted on the other end of the wheel spindle 13.

A feeding mechanism is provided to facilitate adjustment of the wheel slide 11 relative to the base 10 comprising a rotatable feed screw 25. The right hand end of the feed screw 25 is slidably keyed in a rotatable sleeve 26 which is in turn journalled in an anti-friction bearing 27 which is xedly supported by the base 10. The left hand end yof the feed screw 25 is connected to a slidably mounted sleeve 28 which is slidably mounted in a cylindrical aperture 29 formed within the base 10 and arranged in axial alignment with the feed screw 25.

The wheel slide 11 is provided` with a depending bracket 30 which supports a rotatable feed nut 31. The feed nut 31 is journalled in a pair of spaced anti-friction bearings 32 andl33 which are carried by the bracket 30. The feed nut 31 meshes with or engages the feed screw 25. The mechanism is arranged so that either the rotary motion of the feed screw 25 or the rotary motion of the feed nut 31 will impart a traverse adjustment to the wheel slide 11. A worm gear 34 is formed integral with the outer periphery of the feed nut 31. The worm gear 34 meshes with a Worm 35 which is mounted on a rotary shaft 36 (Fig. 2). The shaft 36 is rotatably supported by. a pair of spaced anti-friction bearings 38 and' 39 which are carried by the depending bracket 30. A mechanism to be hereinafter described is provided for imparting a rotary motion to the shaft 36 so as to rotate the feed nut 31 to impart a compensating adjustment to the wheel slide 11.

A hydraulically operated mechanism is -provided for imparting a rapid traverse movement to the wheel slide l 11 to facilitate rapidly moving the wheel slide 11 and the grinding wheel 14 from a grinding to a truing position before and after a grinding wheel truing operation. This mechanism comprises a cylinder 40 which is arranged in axial alignment with the sleeve 28 and the feed screw 25 (Fig. l). The cylinder 40 contains a slidably mounted piston 41 which is connected to the left hand end of a piston rod 42. The right hand end of the piston rod 42 is connected to the sleeve 28. When fluid under pressure is passed through pipes not shown to either end of the cylinder 40 ay longitudinal movement of the piston 41 is obtained to cause a corresponding movement to be imparted to the grinding wheel 14 and the wheel slide 11. This mechanism may be identical with that shown in the United States patent to H. A.- Silven and C. G. Flygare No. 2,522,485 dated September 12,.

1950, to which reference may be had for details of disclosure not contained herein.

A shaft.37 is slidably keyediwithin the right handy end ofthe sleeve 26. The shaft 37 is operatively connected to a manually operable feed mechanism such as,- for example, that disclosed in the above mentioned prior United States patent.

The base also serves as a support for a transversely movable regulating wheel slide 44 which is slidably mounted on a dove-tail slideway 45 formed on the upper surface of the base 10.' The regulating wheel slide 44 supports a rotatable wheel spindle 46 having a regulating wheel 47 supported on one end thereof. A driving mechanism is provided for the regulating Wheel 47 and the spindle 46 comprising an electric motor 48 which is adjustably supported on the upper surface of the slide 44. The motor 48 is provided with a motor shaft 49 having a multiple V-groove pulley 50 which is connected by multiple V-belts 51 with a multiple V-groove pulley 52 which is mounted on the-other end of the regulating wheel spindle 46.

A feeding mechanism is provided for feeding the regulating wheel slide 44 transversely toward and from the grinding wheel 14. This mechanism comprises a rotatable feed screw 55 which is rotatably journalled in a bracket 56 fastened to the base 10 of the machine. The feed screw 55 meshes with or engages a feed nut (not shown) formed within the regulating wheel slide 44. A manually operable feed wheel 57 is mounted on the right hand end of the feedscrew 55. By imparting a rotary motion to the feed wheel 57, the regulating wheel slide 44 may be adjusted transversely in either direction.

A workrest blade 60 is adjustably supported on a frame 61 which is in turn supported on a longitudinally movable slide 62. The slide 62 is supported by spaced anti-friction slideways 63 and 64 on the upper surface of a transversely movable slide 65. The slide 65 is supported by spaced anti-friction bearings 66 and 67 (Fig. 7). A pair of spaced brackets 68 and 69 are fastened in lixed relationship with the base 10. The brackets 68 and 69 support a pair of forming bars 70 and 71 (Fig. 8). The lower formingbar 70 is' provided for producing the desired and determined shape on the periphery of the grinding wheel 14. The forming bar 71 is provided for producing the desired and predetermined shape on the periphery of the regulating wheel 47. The forming bars and 71 are providedl with longitudinal and transverse adjusting screws substantially the same as shown in the pending U.'S. application Serial No. 578,412 led April 16, 1956, now Patent No. 2,834,159, to which reference Vmay be had for details of disclosure illustrated but not described herein. The forming bars 70 and 71 may be independently adjusted in both a longitudinal and transverse direction after whichV they may be clamped in an adjusted position by a pair of spaced clamping screws 72 and 73. The clamping screws pass through elongated slots formed within the forming bars 70 and 71 and are screw threaded into the brackets 68 and 69 respectively.

A follower 75 is supported by a stud 76 on the longitudinally movable slide 62. The follower 75 is provided with a pair of spaced projecting followers 77 and 78. In

the position illustrated in Fig. 6 the follower member 75 is positioned with the follower 77 in engagement with the forming bar 70 for controlling the traverse movement of the slide 65 to produce a predetermined shape on the periphery of the grinding Wheel 14. When it is desired to true the regulating wheel, the follower member 75 is swung in a clockwise direction to swing the follower 78 into position 78a inoperative engagement with the forming bar 71 which controls the movement of the slide 65 so as to produce a. predetermined contour on the periphery of the regulating wheel 47.

A pair of spaced springs 80 (only one of which is shown in Fig. 1 of the drawing)` are 'fastened' between a stud 81 mounted on the slide65 and a-stud 82 mounted on the bracket 56 to yieldably urge the slide 65 in a direction toward the right (Fig. 1) so as to maintain one of the followers 77 and 78 in operative engagement with the forming bar 70 or the forming bar 71 during a truing operation. f

A pair of spaced stop screws 85 and 86 mounted on the frame 61 are arranged to be engaged by a stop surface 87 or a stop surface 88 formed on the upper member 75 when the follower member 75 is in either a grinding wheel or a regulating Wheel truing position.

A hydraulically operated mechanism is provided for traversing the truing tool 117 longitudinally. This mechanism comprises a cylinder 90 (Fig. 11) tixedly mounted relative to the transversely movable slide 65. The cylinder 90 contains a slidably mounted piston 91 which is connected to a piston rod 92, one end of which is fastened to the slide 62. When fluid under pressure is passed through a pipe into a cylinder chamber 97, the piston 91 together with the slide 62 will be traversed toward the right (Fig. l1). During this movement iluid within a cylinder chamber 98 may exhaust through a pipe 96. Similarly when fluid under pressure is passed through the pipe 96 into a cylinder chamber 98, the piston 91 together with the slide 62` will be traversed toward the left. A control valve 100 is provided for controlling the directio-n of movement of uid to the opposite ends of the cylinder 90. The valve 100 is a piston type valve cornprising a valve stern 101 having a plurality of valve pistons formed integrally therewith to form a plurality of spaced valve chambers 102, 103 and 104. The valve is provided with a central passage 105 which interconnects the valve chamber 102 with the valve chamber 104. A compression spring 106 serves normally to hold the valve member 101 in a left hand end position. A solenoid S1 isprovided which when energized serves to shift the valve member 101 into a right hand position as will be hereinafter described. Fluid exhausting from the control valve 100 passes through a pipe 107 through a throttle valve 103 into an exhaust pipe 109. By manipulation of the throttle valve 108, the rate of movement of the piston 91 together with the truing tool slide 62 may be varied and regulated as desired.

The longitudinally movable slide 62 supports a truing tool supporting mechanism comprising a pivotally mounted bracket 110 which is pivotally supported by lopposed pivot screws 111. A compression spring 112 serves to urge `the bracket 110 in a clockwise direction so that an adjustable stop screw 113 carried by the bracket is maintained in engagement with a stop surface 114 which is formed on the frame 61. The bracket 110 is provided with a dovetail slideway 115 which mates with a correspondin'gly shaped way formed on a truing tool holder 116 which supports a truing tool 117. The truing tool holder 116 serves as a support for a truing tool holder 118 which in turn supports a truing tool 119 for truing the surface of the regulating wheel 47. Suitable adjustments are provided for adjusting the truing tool holders 116 and 118 to position them in a vertical direction relative to `the grin'ding wheel 14 and the regulating wheel 47. The mountings for the truing tools 117 and 119 are substantially identical with those shown and described in my pending application Serial No. 578,412 previously referred to, to which reference may be had for details of disclosure not contained herein.

1n the present case the truing tool holder 116 which supports the grinding wheel truing tool 117 is provided with a micrometer adjusting mechanism to facilitate adjusting the truing tool 117 relative to the holder 116 so as to compensate for diamo-nd or truing tool wear.V As illustrated in' Figures 9 and 10 the truing tool 117 is supported in an axially adjustable sleeve 125. The sleeve is supported within a bushing 126 which is located within a' cylindrical aperture 127 formed in the truing tool holder 116 by means of a set screw 128. An adjusting mechanism is provided comprising a screw 129 formed on the lower end of the sleeve 125 which meshes with or engages a nut 130. The nut 130 is provided with an integral worm gear 131 which meshes with a worm 132 which is mounted on the lower end ofra shaft 133. The upper end of the shaft 133 is promatically shown in Figure l1.

s vided with a micrometer adjusting knob y134 to facilitate a precise rotation of the worm 132 to precisely adjust the position of the truing tool 117 so as to compensate for wear. The truing tool holder A116 is provided with a slot 135 and a clamping screw 136 by means of which the sleeve 125 may be clamped in adjusted position.

A fluid pressure system is provided for supplying fluid under pressure to the various actuating mechanisms of the machine. This system comprises a motor driven fluid pump 140 which is started and stopped by a manually operable switch SW2. The pump 140 draws fluid from a pipe 141 from a reservoir 142 and passes fluid under pressure through a pipe 143 to a control valve 144 which is operatively connected to pass iluid under pressure either to the control valve 100 for controlling the longitudinal traversing movement of the truing tool slide 62 or to a control valve 145 which controls the admission to and exhaust of fluid to a booster mechanism to be hereinafter described. i

The control valve 144 is a piston' type valve comprising a slidably mounted valve member 146 having a plurality of valve pistons formed integrally therewith to form a plurality of spaced valve chambers 147, 148 and 149. A compression spring 150 serves normally to hold the valve member 146 in a left hand end position. A solenoid S3 is provided which when energized serves to shift the valve member 146 into a right hand end positi-on so that fluid under pressure from the pipe 143 entering the valve chamber 148 may pass through a pipe 151` 'and 158. The valve member 155 is provided with a central passage 159 which interconnects the valve chamber 156 with the valve chamber 158. A compression spring 160 serves normally to hold the valve member 155 I in a left hand end position. A solenoid S2 serves when energized to shift the valve member 155 into a right hand end position. The control valve 145 serves to control the admission to and exhaust of fluid from the booster mechanism by means of a pair of pipes 161 and 162.

Fluid exhausting from the control valve 145 passes` through a pipe 163, through a throttle Valve 164 into the exhaust pipe 109.l By manipulation of the throttle valve 164 the rate of exhaust of'iluid may be regulated as desired.

In' case it is necessary to true a'vertical side face on the grinding wheel, it is desired to provide a suitable control mechanism to stop the longitudinal traversing movement of the truing tool slide 62 and to provide a booster mechanism to cause a transverse movement of the slide 65 so that the truing tool 117 or the truing tool 119 will move in' a direction normal to the axis of rotation to the grinding wheel 14 and the regulating wheel 47. This booster mechanism comprises a follower 170 which is fastened to the underside of the transverse slide 65. A slidably mounted booster bar 171 is slidably mounted within the base (Fig. 7). A hydraulically operated mechanism is provided for traversing the booster bar 171 relative to the base 10 comprising a cylinder 172 which is fastened to the bracket 69. Thecylinder 172 contains a slidably mounted piston 173. vThe piston 173 is connected by a piston rod 174 with the booster bar 171. In the position of the control valve 145, as shown in Figure ll fluid under pressure enterin'g the valve chamber 157 passes through the pipe 161 into a cylinder chamber 175 to move and hold the piston 173 into a left hand end position with the booster bar positioned as diagram- During movement of the piston' 173 toward the left fluid within a cylinder chamber diseases A k tle valve 164 into the exhaust pipe 109. The setting of the thnottle valve 164 serves to determine the rate of movement of the piston 173. The direction of movement of the piston 173 is reversed when the solenoid S2 is energized.

The piston rod 174 is a double end piston rod having its right hand end operatively connected to a slidably mounted cam bar 177 which is arranged to actuate a limit switch LS3 when the piston 173 is moved longitudinally. The longitudinally movable slide 65 is provided with apslidably supported cam bar 180 which is arranged to slide within a groove 181 formed in a housing 182 which is integral with the slide 65. As shown diagrammatically in Figure 11 the longitudinally movable slide 62 is provided with a pair of spaced lugs 185 and 186 which support stop screws 187 and 188. These screws 187 and 188 are adjusted to provide a loss of motion between the screws and the ends of cam bar 180,`

The cam bar 180 is provided with a pair of spaced V-shape grooves 189 and 190 which are arranged to be engaged by the actuating roller 191 of a limit switch LS2 when the longitudinally movable slide 62 is traversed longitudinally. The limit swich LS2 is fixedly supported relative to the transversely movable slide 65. The booster mechanism together with the limit switches LS2 and LS3 are substantially the same as that disclosed in my prior United States Patent No. 2,647,504 dated August 4, 1953, to which reference may be had for details of disclosure not contained herein.

A feeding mechanism has been illustrated in Figures 2, 3, 4 and 5 to impart a feeding movement to the wheel slide 11 and grinding wheel 1,4 so as to advance the grinding wheel before each pass of the truing tool across the operative face of the grinding wheel and also to impart an unwind and windmotion to the feed nut 31 at the time of each feeding movement thereof. As illustrated in Figure 2, the shaft 36 is provided with a bevel gear 200 which meshes with a bevel gear 201 mounted on the left hand end of a rotatable shaft 202. The shaft 202 is journalled in spaced bearings 203 and 204 which are xedly mounted relative to the wheelv slide 11. The right hand end of the shaft 202 serves as a support for an oscillatable feeding unit 205. The

feeding unit 205 comprises a pair of feeding mechanisms -206 and 207 for independently advancing the grinding wheel before each traversing movement of the truing tool in either direction. v

The feeding mechanism 206 comprises a cylinder 208 which contains a slidably mounted piston 209. The piston 209 is normally held in a downward position by a compression spring 210. When fluid under pressure is passed through a pipe 211 into acylinder chamber 212,

the piston 209 is moved upwardly until an integral stud 213 formed on the upper end of the piston 209 engages an adjustable stop screw 214. The piston 209 is providedv with a spring pressed pawl 215 which is arranged to engage the teeth of a ratchet wheel 216 which is fixedly mounted on a rotatable shaft 217. The shaft 217 is provided with a gear 218 which is slidably keyed onto the left hand end thereof (Fig. 2). The gear 218 meshes with a gear 219 keyed on the shaft 202. During the upward movement, of the piston 209, the pawl 215 rides idly over the teeth of the ratchet wheel 216. When tiuid under pressure is exhausted from the cylinder chamber 212 ina manner to be hereinafter described, the released compression of the spring 210 causes a downward movement of the piston 209. During the downward movement of the piston 209 the pawl 215 engaging theY teeth of the ratchet vwheel 216 imparts a counterclockwise rotary motion to `the ratchet wheel 216 Y which is transmitted through the shaft 217, the gear 218, the gear 219 to rotate the shaft 202 and through the mechanism previously described to impart a rotary motion to the feed nut 31 so as to advance the grinding wheel slide 211 and the grinding wheel 14 by a predetermined increment before the truing tool starts a longitudinal movement toward the right (Figure ll).

The feeding mechanism 297 is substantially identical with that just described and comprises Va cylinder 225 containing a slidably mounted piston, 229, which is normally held in a downward position by a compression spring 220. When fluidunder pressure is passed through a pipe 221 into a cylinder chamber 222 to cause an upward -movement of the piston 225, a spring pressed pawl 225 engaging theteeth of the ratchet wheel 216 imparts a rotary motion to the ratchet wheel 216 and through the gear mechanism previously described to impart a rotary motionto the feed nut 31 so as to advance the grinding wheel slide 11 and grinding `wheel 1d by a predetermined amount before the truing tool 117 starts its traversing movement toward the left. The upward movement of the piston 229 continues until a stud 223 formed integral with the upper end of the piston 229 engages an adjustable stop screw 224. By manipulation of the stop screws 214 and 224, the extent of the infeeding movement of the grinding wheel before each pass of the truing tool may be independently regulated, as desired. The mechanism just described serves to impart a relatively coarse infeed before each traverse of the truing tool.

If a line feeding. increment is desired before each traverse of the truing tool, another mechanism to be hereinafter described is employed. The piston 229 is provided with a spring pressed pawl 230 which is arranged to engage the teeth of a ratchet wheel 231 which is fxedly mounted on a rotatable shaft 232 (Figures 3 and The shaft 232 is provided with a worm 233 which meshes with a worm gear 234 which is rotatably mounted on the shaft 217. The pawl 230 serves during the downward movement of the piston 299 to impart a clockwise rotary motion to the ratchet wheel 231.

The piston 2119 is similarly provided with a pawl 240 (Fig. 4) which is arranged to engage the teeth of a ratchet wheel 241 (Fig. 3) which is also iixedly mounted on the shaft 232. The pawl 24@ serves during the downward movement of the piston 219 to impart a feeding increment through the ratchet wheel 241 and the mechanism previously described to the feed nut 31.

The ratchet wheel 216 and the worm gear 234 are both rotatably supported on the shaft 217. A clutch mechanism is provided comprising a clutch pin 245 which may be moved either toward the right or toward the left by an'actuatingknob 246 to lock either the ratchet wheel 216 or the worm gear v234i to the shaft 217. When the worm gear 234i is locked to the shaft 217, a relatively fine feeding increment is imparted through either the ratchet wheel 231 or the ratchet wheel 241 to impart a feeding increment to the feed nut 31. It will be readily apparent from the foregoing disclosure that either a relatively fine feeding movement of the grinding wheel may be obtained before each pass of the truing tool across the operative face of the wheels, or a coarse feed may be obtained as desired. When the clutch knob 246 is moved toward the right (Fig. 2), the worm gear 234 is locked to the shaft 217 so as to render the line feeding mechanism operative. When the knob 246 is moved into a left hand end position, the ratchet wheel valve chambers 267Yand 263.

ably accomplished by a hydraulically operated mech anism comprising a cylinder 255 (Fig. 11) which contains a slidably mounted piston 256. The cylinder 255 is pivotally connected at its right hand end to the wheel slide 11 by means of a stud 257. The piston 256 is connected to the right hand end of a piston rod 258 (Fig. 11). The endof the piston rod is tixedly connected to a block 259 which is in turn connected by a pivot stud 260 with the feeding unit 265. A compression spring 261 serves normally to hold the piston 256 in a left hand end position. When liuid under pressure is passed through a pipe 262 into a cylinder chamber 263, the piston 256 together with the piston rod 258 will be moved toward the right so as to rock the feeding unit 2115 in a counter-clockwise direction about the axis of the shaft 262 thereby imparting an unwinding movement to the feed nut 31. The piston 256 returns rapidly to a left hand end position under the influence of the released compression spring 261 to rock the feeding unit 2115 in a clockwise direction thereby imparting a wind motion to the feed nut 31 so as to take up any back-lash in the feed mechanism parts following each feeding movement.

A gear 216:1 is formed integral with the gear 216. The gear 216a is normally held against rotation by a spring pressed pawl 216.5 (Figs. 2 and 4). The gear 213 is keyed to the shaft 217. When the clutch pin 245 is engaged to connect the shaft 217 either to the gear 216 or to the worm gear 234, a rotary motion may be imparted to the shaft 217 either by actuation of the ratchet wheel 216 or the ratchet wheels 231-241 to impart a feeding motion through the gear 213 and the gear 219 to the feed nut 31. The compressionspring holding the pawl 216b in engagement with the gear 21611 is sufficient to prevent rotation of the shaft 217 and the gear 218 when the feeding unit 205 is rocked to impart an unwind and a wind motion tothe feed nut 31.

A fluid pressure actuated pressure control valve 265 is provided for controlling the admission of iiuid under pressure to the feed cylinders 208 and 223 and also to the cylinder 255 to produce the wind and unwind movement. The valve 265 is a piston type valve having a slidably mounted valve member 266 which is provided with a plurality of spaced valve pistons to form spaced The valve 265 is co-ntrolled by the control valve 1G19. A pipe 269 and a pipe 274) connect the valve 1d@ with the shuttle type valve 265.

The valve 265 is also connected to a control valve 275 for controlling the admission to and exhaust of fluid rom the cylinder 255. The valve 275 is a piston type valve having a slidably mounted valve member 276 formed with a plurality of valve pistons to form spaced valve chambers 277 and 27S. A compression spring 279 serves normally to hold the valve member 276 in a left hand end position.

When the solenoid S1 is energized, the valve member 1111 moves into a right hand end position so that iluid under pressure from the pressure pipe 151 enters the valve chamber 103 and passes through the pipe 95 to start the piston 91 together with the truing tool 117 toward the right. At the same time fluid under pressure entering the valve chamber 123 passes through the pipe 269 into the valve chamber 267, through the pipe 211 into the feed cylinder chamber 212 to cause an upward movement of the piston 229 to impart an infeeding movement in a manner previously described to impart an -infeeding movement tothe wheel slide 11 and the grinding wheel 14. At the same time fluid under, pressure within the pipe 211 enters a left hand end chamber in the valve 275 to shift the valve member 276 toward the right. During this movement when the valve chamber 277 uncovers a port at the end of the pipe 211 fluid under pressure is passed through the pipe 262 to move the piston 256 toward the right thereby imparting a counterclockwise movement-to the feed unit 205 to impart an unwindpmovement to the feed nut 31. During i the movement of the valve member 276 toward the right the ports at the end of the pipes 221 and 286 are closed by the center valve piston.

At the same time fluid under pressure passing through the pipe 269 enters a left hand end chamber of the valve 265 to move the slidably mounted valve member 266 toward the right. As the valve member 266 approaches the right hand end of its stroke, a port at the end of the pipe 269 is blocked and a port at the end of an exhaust pipe 285 is opened to the valve chamber 267 so that the uid within the cylinder chamber 212, within the left hand end chamber of the valve 275 may exhaust through the pipe 211 into the valve chamber 267 and exhausts through the pipe 285 to the reservoir 142. The released compression of the spring 279 shifts the valve member 276 toward the left so that fluid from the cylinder chamber 263 may exhaust through the pipe 262, through the valve chamber 277 and through a piper286, through exhaust pipe 285 to the reservoir 142. During the exhaust of uid from the'cylinder chamber 263, movement `of the piston 256 serves to impart a clockwise wind movement to the feed unit 265 which imparts a wind movement to the feed nut 31. Due to the fact that less pressure is required to actuate the feed piston 269 and the wind piston 256, the infeed will be obtained and the unwind and wind motion `of the feed unit will be obtained bef-ore the truing tools move into operative engagement with the grinding wheel 14 during the right hand movement of the piston 91 and the slide 62. The

truing tool contains its traverse across the operative` face of the grinding wheel to true the same to the desired and predetermined contour.

As the truing tool and its supporting slides 62 approaches the right hand end of its traversing stroke the limit switch LS1 is opened to deenergize a relay switch CRI thereby deenergizing the solenoid S1 so that the released compression of the 4spring 106 moves the valve member 101 to a left hand end position, as shown'in Figure l1. With the valve in this position uid under pressure is passed through the pipe 96 into the cylinder chamber 98 tostart movement of the piston 91 together with the slide 62 toward the left. At the Sametime fluid under pressure from the valve chamber 103 is passed through the pipe 270 through the valve chamber l 268, through the pipe 221 into the cylinder chamber 222 to cause an upward movement of the piston 229 to impart an infeeding movement to the wheel slide 11 and the grinding wheel 14. Fluid under pressure is also passed through the valve chamber 278 into the cylinder chamber 263 to cause the piston 256 to move toward the right so as to rock the feed unit 205 in a counterclockwise direction thereby imparting an unwind movement to the feed nut 31. At the same time uid under pressure passing through the pipe 270 enters a right hand end chamber in the valve 265 to shift the slidably mounted valve member 266 toward the left into the position shown in Figure 11. During this movement the port at the end of the pipe 270 is closed and a port at the end of the pipe 285 is opened. ln this position of the parts uid within the cylinder chamber 222 and the cylinder chamber 263 may exhaust through the pipe 221, through the valve chamber 268 and through the pipe 285 into the reservoir 142. This exhausting of fluid allows the piston 219 to return to the position illustrated in Figure 1l and also allows the piston 256 to move toward the left thereby rocking the feeding unit 225 in a clockwise direction to impart a wind movement to the feed nut 31.

The operation of the improved truing apparatus will be readily apparent from the foregoing disclosure. The main switch SW1 isvmanually closed. The switch SW2 is closed to start the pump driving motor 140. The switch SW3 is closed to start the grinding wheel motor 15 and the switch SW4 is 'closed to start the regulating 10 wheel driving motor. The closing of the switch SW1, through the now closed contacts 295 of the limit switch LS2 serves to energize the solenoid S3 to shift the valve member 146 into a right hand end position so that fluid under pressure from the pump 140 entering the valve chamber 148 passes through the pipe 151 to the valve chamber 103. In the position of the valve as illustrated inpFigure 11, fluid entering the valve chamber 103 passes through the pipe 96 into the cylinder chamber 98 to hold the piston 91 together with the slide 62 and the truing tools 117 and 119 in a left hand end position.

To start a truing cycle, the switch PBI is momentarily closed. The closing of switch PB1 serves, through the now closed limit switch LS1 to energize the relay switch CRI thereby closing two sets of contactors 290 and 291. The closing of contactors 290 serve to energize the solenoids S1 and S2 to shift the valve members 101 and 155 into right hand end positions. The closing of the contactors 291 serves through the limit switch LS1 to set up a holding circuit to maintain the relay switch CRI energized.

The shifting of the valve member 101 to a right hand end position passes fluid under pressure from the valve chamber 103 through the pipe 95 into the cylinder chamber 97 to move the piston 91 together with the slide 62 and the truing tools 117 and 119 toward the right. At the same time uid under pressure from the valve chamber 103 passes through the pipe 269, through the valve chamber 267 through the pipe 211 into the cylinder chamber 212 toV cause an upward movement of the piston 209 thereby imparting an infeeding movement to the grinding wheel slide and the grinding wheel 14. At the same time fluid under pressure enters the left hand end 'chamber in the valve 275 to shift the slidably mounted valve member 276 toward the right so that uid under pressure within the pipe 211 passes through the valve chamber 277, through the pipe 262 into the valve chamber 263 to move the piston 256 toward the right thereby imparting counter-clockwise motion to the feed unit 205 to impart an unwind movement to the feed nut 31.

At the same time uid under pressure passing through the pipe 269 enters the left hand end chamber of the valve 265 to move the slidably mounted valve member 266 toward the right. Movement of the valve member 266 toward the right serves to close the port at the end of th'e pipe 269 and to open the port at the end of the exhaust pipe 285 so that fluid under pressure may exhaust from the cylinder chamber 212, from the left hand end chamber of the valve 275 so that the valve member 276 moves into a left hand end position thereby allowing fluid to exhaust from the cylinder chamber 263 under the influence of the released compression of the spring 261 thereby rocking the feed-unit 205 in a clockwise direction to impart a wind movement to the feed nut 31.

The infeeding movement of the grinding wheel and the unwind and wind movement of the feed unit require less pressure to operate and therefore complete their operation before the truing tool 117 and the slide 62 start traversing toward the right to bring the truing tool 117 into engagement'with the grinding wheel 14. During the traversing movement toward the right, the follower 77 rides on the face 70a of the forming bar 70 to position the truing tool 117 for truing the face 14a of the grinding wheel 14. The truing tool 117 continues its traverse toward the right until it reaches the rst shoulder on the grinding wheel 14. During this movement of the slide 62, the stop screw 187 engages the end of the cam 180 after which movement of the slide 62 traverses the cam bar 180 toward the right until the actuating roller 191 of the limit 1 1 valve member 146 moves to a left hand end position thereby cutting o the flow of uid under pressure through the pipe 151 and the valve 199 to stop .the longitudinal movement of the piston 91 and the slide 62 with the truing tool 117 in engagement with the first shoulder of the grinding wheel 14. The solenoid S2 has been previously energized so that the valve member 155 is in a right hand end position to pass fiuid under pressure through the -pipe 162 into the cylinder chamber 176 to move the booster piston 173 and the booster cam bar 171 toward the right. As the cam bar 171 moves toward the right, the foliower 1713 rides down an incline face 171:1 on the bar 171 and the follower 77 rides down a shouldered face at theright hand end of the portion 76a of the forming bar 76 thereby allowing the tension of the spring 6@ to impart a transverse movement to the slide 65 so that the truing tool rides up the first shouldered face on the grinding wheel 14. At the same time movement of the piston 173 toward the right serves to `impart-av corresponding movement to the cam bar 177 so that the actuating roller of the limit switch L53 rides into a portion 17701 on the cam 'bar 177 thereby opening the contactors 296 and closing the contactors FJhe closing of the contactors 297 serves to energize the relay switch C112. The contactors 294 of the limit switch L52, being now closed serves through the contactors 293 to set up a holding circuit to maintain the relay switch C112 energized.

During the movement of the piston 173 and the booster cam bar 171 'toward the right the follower 170 rides across the plane face on the bar 171 and down the incline onto the second plane face on the bar 171. At this time the projection 177]) on the cam bar 177 engages the actuating roller of the limit switch L53 and again actuates LS3 so as to close the contactors 296 and open the contactors 297 (Figure 1l). r1`he closing of contactors 296 serves through the now closed contactors 292 of the relay switch C112 to again complete a circuit to energize the solenoid S thereby to shift the valve member 146 into a right hand end position. In this position of the valve 146, fluid is cut off from the pipe 152 and passes through the pipe 151 and through the pipe 95 to again start the movement of the piston 91 with the slide 62 and the truing tool 117 toward the right. During this movement. toward the right of the slide 62 the follower 77 rides along the face 70h of the forming bar 71D and the truing tool 117 lpasses across the face 1411 of the grinding wheel 14. Movement of the slide 62 serves to move the cam bar 160 vtoward the right until the V-shaped notch 19@ serves .to swing the actuating roller 191 of the limit switch L82 so as to open the contactors 294 and to close the contacts 2% so that the limit switch LS2 assumes the position as illustrated in Figure 1l. The opening of contactors 2941 serves to break the holding circuit to deenergize the relay switch CK2. The closing of contactors 295 serves to hold the solenoid S3 energized so that the piston91 continues its movement toward the right. This movement of the piston 91 together with the slide 62 and the truing tool 117 continues until the truing tool traverses into engagement with the next shoulder on the grinding wheel 14 between the operative face 14;!) and 14e. During this movement the follower 77 engaging the forming bar 7@ rides along the face 76h. Movement of the slide 62 toward the right continues until the actuating roller 191 of the limit switch LSZ drops into a J-shaped notch 189 whichserves to actuate the limit switch LSZ in a manner previously described to deenergize the solenoid S3 thereby stopping the longitudinal movement of the piston 91 and at the same time starting the movement of the piston 173 toward the right so that the follower 17@ rides down the incline 171b on the booster cam bar 171 thereby allowing the released tension of the spring 8@ to impart a traverse movement to the slide 65 to traverse the truingvtool 117 up the shouldered face between the surfaces 14h and 14C on the grinding wheel 14. l.

As the piston 73 moves toward the right, the cam bar 177 moves toward the right until the face 177e actuates the limit switch LS3. The actuation of the limit switch L83 serves in a manner previously described to stop the movement of the piston 173 thereby stopping the movement of the booster cam bar 171 and at the same time starts the movement of the piston 91 together with the slide 62 and the truing tool 117 toward the right to tru the face 14e of the grinding wheel 14. During this movement the follower 77 rides across the face 70C of the forming bar 70.

When the slide 62 reaches the end of its movement toward the right, it engages and opens the limit switch LS1 to deenergize to break the holding circuit thereby deenergizing the relay switch CR1. Deenergizing relay relay switch CRI serves to deenergize the solenoids S1 and S2. The deenergizing of the solenoid S1 shifts the valve 101 into the position illustrated in Figure 11 so that Huid under pressure is passed through the pipe 270 to move the valve member 266 toward the left previous to which iuid passes through the valve chamber 268, through the pipe 221 into the cylinder chamber 222 to actuate the feed piston 229. At the same time fluid under pressure passes into the cylinder chamber 263 to impart an unwind movement to the feed nut 31 in a manner similar to that previously described. As the valve member 266 approaches the end of its movement toward the left fluid may exhaust from both the cylinder 213 and the cylinder 255 thereby imparting a wind motion to the feed nut 31.

At same time the solenoid S1 is deenergized to shift 'the valve member 101 into a left hand end position fluid under pressure is passed through the pipe 96 into the cylinder chamber 9% to start movement of the piston 91 together with the slide 62 and the truing tool 117 toward the left. During the return movement of the slide 62, the solenoid S2 being deenergized, uid under pressure is passed through the pipe 161 into the cylinder chamber 175 so that the booster cam bar 171 when actuated is moved toward the left. rThe operation of the piston 91 together with the booster piston 173 is substantially identical to that just described in connection with the traversing movement toward the right.

in case a continuous truing cycle is desired, a switch SW5 may be closed so that when the slide 62 reaches the end of its return stroke toward the left, a normally open limit switch L83 will be closed to again energize relay switch CR1 and start a second reciprocation of the truing tool 117. As long as the switch SW5 remains closed the truing tool 117 will be reciprocated across the operative face of the grinding wheel in a manner the same as the above described. When it is desired to stop co-ntinuous truing the switch SWS is opened so that the truing tool 117 will make only one complete reciprocation and then stop.

The regulating wheel requires truing only at very infrequent times since there is very little wear on the surface thereof. The follower 75 is rocked in a clockwise direction so as to Vswing the follower projection 78 into position 78a (Fig. l1) into operative engagement with the forming bar '71. At the same time the follower 77 is moved out of operative engagement with the forming bar 741. A pair of valves 300 and 301 are provided in the pipes 269 and 270 respectively. To facilitate rendering the feed unit 205 inoperative during a regulating wheel truing operation the valve in this position serves to supply fluid under pressure only to the valve 1110.

When it is desired to Start a truing cycle of the regulating wheel 47, the switches SW6 and PE1 are closed to energize the relay switch C111 which serves to energize the solenoid S1 to control the passage of uid to the cylinder 96. At the same time the solenoid S2 is energized but has no operative function since the valve 1414 is maintained in a right hand end position during the entire regu- 13 95 to start the piston 91 moving toward the right to traverse the truing tool 119 across the operative face of the regulating wheel 47. During this movement of the truing tool 119, the traversely movable slide 65 is controlled by the follower 78 riding the operative face of the yforming bar 71. The movement of the slide 62 and the piston 91 continues toward the right until the slide 62 opens the normally closed limit switch LS1 to deenergize the relay switch CRI thereby deenergizing the solenoid S1 to reverse the flow of fluid to the cylinder 90. If desired, the feed wheel 57 may be actuated to advance the regulating wheel 47 toward the truing tool 119 before it starts its movement toward the left. The piston 91 moves toward the left to again pass the truing tool 119 across the face of the regulating wheel 47 during which movement the traversely movable slide 65 is controlled by the follower 78 riding upon the forming bar 71. The truing operation stops automatically after one complete reciprocaticn of the truing tool 119. If a continuous truing operation is desired on the regulating wheel 47, the switch SWS may be closed to render the switch LS3 operative so that the truing tool will be continuously reciprocated in a manner previously described.

During the truing of the shape indicated on the regulating wheel the operation of the booster cylinder 172 together with the limit switches LSZ and LS3 are ineffective. If the shape to be produced on the regulating wheel requires the use of the booster mechanism then the switch SW6 may be left open and the cycle described in connection with the truing of the grinding wheel may be employed.

A switch PBZ is provided to facilitate stopping a truing cycle at any time if occasion requires. The opening of this switch serves to break theholding circuit to immediately deenergize the relay switch CRl so that the parts return to their initial position.

I claim:

1. In a grinding machine having a transversely movable rotatable grinding wheel, means including a rotatable feed screw and a rotatable nut to feed said wheel transversely in either direction, means to rotate said screw to impart a grinding feed to said wheel, means to impart a rotary motion to said feed nut so as to impart a truing feed to said-grinding wheel, an oscillatable feeding unit, a pawl and ratchet mechanism on said unit to impart an incremental rotary motion to said feed nut to advance the grinding wheel for a truing operation, and means operatively connected to oscillate said unit in timed relation with actuation of the pawl and ratchet mechanisms to impart an unwind and a wind motion to said feed nut in timed relation with the feeding movement thereon.

2. In a grinding machine having a transversely rotatable grinding wheel, means including a rotatable feed screw and a rotatable nut to feed said wheel transversely, means to rotate said screw to imparta grinding feed to said Wheel, means to impart a rotary motion to said nut so as to impart a truing feed to said grinding wheel, an oscillatable feed unit, a fluid pressure actuated pawl and ratchet mechanism on said feed unit operatively connected to impart an incremental rotary motion to said feed nut to advance the grinding wheel for a truing operation, and means including a fluid motor operatively connected to oscillate said unit in timed relation to the actuation of the pawl and ratchet mechanisms to impart an unwind and a wind motion to said feed nut in timed relation with the feeding movement thereof.

3. In a griding machine having a transversely movanism on said unit to impart an incremental rotaryrmotion to said shaft and said feed nut to advance the grinding wheel for a truing operation, andV means including a piston and cylinder operativelyv connected to oscillate said unit in timed relation lWith the pawl and ratchet to impart an unwind and a wind motion to said feed nut in timed relation with the feeding movement thereof.

4. In a grinding machine, as claimed in claim 3, in combination with the parts and features therein specified of a control valve mechanism, operative connections between said valve mechanism and said unit to control the admission to and exhaust of uid from the pawl and ratchet mechanisms and the piston and cylinder for oscillating said unit.

5. In a grinding machine, as claimed in claim 3, in combination with the parts and features therein specified of a longitudinally traversable truing tool, means including a fluid motor to traverse said truing tool in either direction, a control valve for said motor, and operative connections between said control valve and said pawl and ratchet mechanism and said piston and cylinder to impart a truing feed to said grinding wheel and an oscillation to unwind and wind said feed nut before each traversing stroke of the truing tool.

6. In a grinding machine, as claimed in claim 3, in combination with the parts and features therein specified of a control mechanism simultaneously to control the admission of fluid under pressure to one of said pawl and ratchet mechanisms to impart a rotary feeding unit to said feed nut and to said cylinder to oscillate said unit so as to unwind and to wind said nut to facilitate taking up backlash in said feed mechanism.

7. In a grinding machine, as claimed in claim 3, in combination with the parts and features therein specified of a pair of fluid pressure actuated pawl and ratchet mechanisms on said unit, each mechanism being operatively connected to impart an incremental feed to said shaft and feed nut to advance the grinding wheel before each pass of the truing tool across the face thereof, a uid pressure piston and cylinder operatively connected to oscillate said feed unit in timed relation with actuation of the pawl and ratchet mechanisms to impart a rotary unwind and a wind motion to said feed nut to facilitate taking up backlash in the partsl at each actuation of the feed unit.

8. In a grinding machine as claimed in claim 3, in combination with the parts and features therein speciied of means including a worm and worm gear mechanism to actuate said feed nut, a rotatable shaft to actuate said Worm gear mechanism, a rotatable shaft to actuate said mechanism, an oscillatable feed unit on said shaft to actuate said worm and worm gear mechanism comprising a pair of fluid pressure actuated pawl and ratchet mechanisms operatively connected to impart a rotary motion to said worm -gear mechanism before each stroke of the truing tool so as to advance the grinding wheel a predetermined amount before each pass of the truing tool across the operative face of the grinding wheel, and means including a piston and cylinder operatively connected to oscillate said unit in timed relation with the pawl and ratchet mechanism to impart an unwind and :t wind motion to said feed nut.

9. In a grinding machine having a grinding wheel truing apparatus comprising a longitudinally movable slide, a truing tool thereon, a piston and cylinder to traverse said slide longitudinally a truing tool on said slide, a transversely movable slide to Support said longitudinally movable slide, means including a nut and screw to feed said slide transversely means to -rotate said screw to impart a feedingand positioning movement to the grinding wheel, means including a feed compensating unit including a pair of independently operated piston and cylinder actuated pawl and ratchet mechanisms oper- 15 16 atively connected to impart a rotary motion to the feed References Cited in the le of this patent nut, and a control Valve mechanism operatively conn nected to control the admission to and exhaust of uid UNITED STATES PATENTS from the pawl and ratchet mechanisms, and to impart a 2,522,485 Silven et a1. Sept. 12, 1950 rotary motion to said feed unit to impart an unwind and 5 2,647,504 Hill Aug. 4, 1953 a Wind motion to said feed nut. 2,745,221 Comstock May 15, 1956 

